The present invention relates generally to devices which provide stiffening reinforcement for catheters and other medical probes for placement into the body of a patient. In particular, this invention relates to stylet wire assemblies which are to be maintained in place within a catheter while the catheter is being used for fluid infusion or evacuation.
Many medical procedures require the insertion of a catheter into the body. Catheters are usually made of flexible or pliable material to facilitate insertion into and advancement within the body. These devices, however, sometimes lack sufficient rigidity when used in certain situations and require reinforcement in order to maintain their desired structures. Stylet wires used to stiffen catheters for this purpose are well known in the prior art.
In some situations, it is necessary to maintain the stylet wire in place while the catheter is being used for fluid infusion or evacuation. When this is done, access into and through the fluid conduit of the catheter must be kept open while the stylet is in place within the catheter. This is commonly accomplished by using a T-fitting which connects to the proximal end of the catheter. With the stylet wire inserted into the catheter through an axial opening in the T-fitting, fluids can be inserted and/or evacuated through the T-fitting's transverse port. The fitting of catheters with T-fittings for this purpose adds to the cost of manufacturing these devices, and sometimes unnecessarily so, since they do not always need to be used in conjunction with a stylet wire in place. Also, when such a catheter fitted with a T-fitting is used for infusion or evacuation without a stylet wire in place, the user of the device must first be sure to cap the second port on the T-fitting. If the cap is not properly placed, or is forgotten, fluids may leak or even spurt out through this unsealed port causing, at the least, inconvenience, and possibly even, failure of the procedure.
Prior art devices have also been designed which have incorporated into the stylet wire assembly itself the capability to provide fluid communication through the catheter while the stylet wire is in place within the catheter. U.S. Pat. No. 5,026,351 to Dizon discloses an IV stylet catheter having a housing attached to a stylet which is received into the catheter. The Dizon device allows fluid to be injected through the housing and into the catheter with the device placed therein. U.S. Pat. No. 4,659,328 to Potter et al. and U.S. Pat. No. 4,798,593 to Iwatschenko also disclose structures which incorporate a fluid communication fitting into a stylet wire assembly to allow for fluid communication through a catheter while the stylet wire is in place. In each of these prior art devices, fluid communication is necessarily constricted by the anchoring of the wire within the housing of the assembly, as any fluids must pass the anchoring structure in order to enter or exit the assembly. The anchorage of the wire in these devices thus presents an obstruction to the flow of fluid through the catheter, thereby preventing the catheter from functioning as optimally as possible.